The officers then take their posts to watch for razor blades in tin foil, knives in backpacks and Vaseline on students' faces, which is used to prevent scratches during fights. As the students enter the building, they have to file through metal detectors, some even emptying their pockets before being cleared to go to class.

"This is a dangerous school," said 15-year-old Julissa. "A lot of fights pop off over nothing, so you got to be safe."

Strawberry Mansion High, where 94 security cameras line the halls, had 435 students at the beginning of this school year. Located in a poor neighborhood with a high crime rate, Strawberry Mansion has been on the state of Pennsylvania's "Persistently Dangerous Schools" list for the past five years.

ABC News' Diane Sawyer and ABC News producers followed the daily lives of the school's students and faculty during the 2012-2013 school year. So far this school year, there have been 49 incidents from fires to teacher attacks reported in or near the school. ABC News' cameras captured students brawling in the cafeteria and being bullied, as well as students who shared their dreams of going to college.

Last year, Strawberry Mansion was among 37 Philadelphia schools that were scheduled to close this June. The city is in the midst of fighting an education budget crisis.

The current principal is Linda Cliatt-Wayman -- the fourth the high school has had in four years. Before coming to Strawberry Mansion, she was an assistant superintendent of high schools for the Philadelphia public school system. Since she started last fall, the number of incidents has been cut in half.

"I could not find a principal who was suitable to handle this school," Cliatt-Wayman said. "Therefore, I said to myself, because I love these students dearly and I knew the community ... I would just volunteer to be the principal."

Philadelphia School District Superintendent William Hite said finding strong leadership for Strawberry Mansion has been the "primary factor" in starting the school's turnaround.

"The type of persona, if you will, who establishes a clear vision for what appropriate behavior looks like, for what rigorous instruction looks like, for expectations, that students are exposed to opportunities," Hite said. "If turnaround can happen here, at Strawberry Mansion, it can happen anywhere in the country."

In her effort to protect the student body, Cliatt-Wayman banned boots, which can be used to stomp on heads, and hoodies so students can't hide from security cameras.

"Each day, it gets scarier," Cliatt-Wayman said. "[The student] just said to me, 'I have a bullet with your name on it.' That's what it was. And I know that guns are really accessible in this neighborhood, so I don't think it's unreasonable that he can get his hand on a gun and shoot me."

But for every student that causes trouble, there are many more who just want to learn. Razzaq, a freshman at Strawberry Mansion, shows up to school even though he shoulders much of the responsibility at home.

Razzaq's favorite subjects at school are chemistry and algebra, and his pride and joy is his Junior ROTC uniform.

When it comes to protecting himself at school, he said, he tries to avoid trouble.

"I use my words," he said. "I don't try to be big. I don't try to be anything."

Another freshman, a small, quiet girl named Malaysia, is also trying hard to make it at Strawberry Mansion.

On parent-teacher conference day, her father came to talk with her algebra teacher. Of the teacher's 70 students, Malaysia's father was the only parent to show up.

"I can't see not wanting to know about your child," said her father, Roosevelt Paramour. "I can't see not wanting to know about their progress and what they are doing."

Paramour works in construction and wants his daughter to have a better life, but there are so many distractions at school. Malaysia said she is bullied a lot. This semester, she was punched in the face after school by another girl.

Judy Williams, the school nurse, treated her busted lip.

""[Strawberry Mansion students] might not have heat, they might not have food, and they're coming to school every day," Williams said. "They see so much in their short period of their lives that most people don't see in a whole lifetime."

Many Strawberry Mansion students struggle with their personal lives. One student, Lorraine, 17, spent two months in a youth detention center last year, for using a blade to slice a girl's face during a fight, but she is trying to get her life back on track and hopes someday to be a nurse.

Another student, Greg, 17, has been in juvenile detention on and off. He said he doesn't believe anything can be done to change the school's violent environment.

"I look at it as you are not going to change people's opinions, you're not going to change any mindset," he said. "They're going to do what they're going to do. ... I just make up my own [rules]. I know the consequences behind my decision."

But many other students said they have big aspirations for college or the armed forces. Others want to work in law enforcement to help make the neighborhood a safer place to live.

Principal Cliatt-Wayman grew up in the Strawberry Mansion neighborhood. On Sundays, she said, her mother would take her and her siblings on the free bus to other neighborhoods so they could see a different way of life.

"She would point out different things for us along the way so to inspire us to really want more," Cliatt-Wayman said. "My mother said, 'Well, none of us ever been to college, but there must be some truth to it because, I believe, that people who maybe go to college is not poor.'"

Cliatt-Wayman is trying to pass on the lessons of her mother to the students at her school, even helping to pay for kids to go on college trips.

"I always want to afford my students opportunities to see things, to see the world, to let them know there's a life other than North Philadelphia," Cliatt-Wayman said. "These kids are the future, and we have to make sure that they are provided with hope and direction."

Strawberry Mansion is also a school with dedicated teachers, some who have been here for years, others who are brand new. Evan Kramp, the school's new history teacher, said he is not afraid to be at school.

"They're children ... and they're coming to school," Kramp said. "Nobody wakes up in the morning and says to themselves, 'I want to be a failure.'"

"There's a student, at the top of his class, a straight-A student, and I know he's been through hell this year. He has not had a permanent place to stay," said Terri Campbell, an English teacher. "[But] he has been accepted to college. So I feel like if he could do it, they all can do it."

In a neighborhood where 40 percent of the people live in poverty, Cliatt-Wayman said she hopes all of her students aspire to go to college so they can have a chance at a better life. Of the 92 students in the graduating senior class, 55 have been accepted to a four-year or community college, but some can't afford the deposit fees.

"If I had the $550 to go to Philadelphia University, I would go," said Christine, a senior.

Despite their struggles, the school district superintendent said Strawberry Mansion will continue to push forward.

"It can never be too hard or hopeless," Hite said. "Once we lose hope then we run the risk of losing a whole bunch of children, and losing a whole bunch of lives."

At the end of the school day, Cliatt-Wayman was in her office, making an announcement to the student body over the school's intercom.

"I want you to be careful going home today, young people," she told them. "You all have to remember that education is the only way. It is your only ticket, and remember if nobody told you they loved you today, you remember I do. I look forward to seeing you in school, on time, on Monday. Have a great day when the bell sounds."